There are several surgical procedures, such as cardiac bypass, fat grafting, and flap reconstruction to name a few, whose success relies heavily upon the revascularization or reprofusion of the surgical site.
One technique for evaluating the vascularization or reprofusion of the surgical site or area of interest is to use near infrared fluoroscopy equipment such as the SPY® Imaging System (Novadaq Technologies, Inc., FL) which is used to visualize blood flow in vessels and micro-vessels in real-time during a surgical procedure.
The SPY® Imaging System exposes an area of interest with near infrared light and records and displays the fluorescence stimulated by the light. For vascularization studies, the fluorescence comes from an intravenous injection of the fluorescent dye, i.e., Indocyanine Green (ICG), that bonds with the proteins in blood. Once in the circulatory system, the infrared light from the SPY® system penetrates deep into the area of interest causing the dye in the area to fluoresce. The camera viewing the area detects the invisible fluorescence and the system processes the information and displays it for the surgeon. The brighter the displayed area, the more blood flow while the darker the area, the lower the blood flow, if any.
One short coming of the system is the integration of the image on the display to that of the surgical site. Because the camera is tuned to be most sensitive to the invisible fluorescence wavelength, normally visible features such as skin anatomy or markings from surgical pens are not viewable on the display of the system simultaneously with the fluorescent image. As a result, it is difficult for the surgeon to relate the exact area of interest to the image on the SPY® display. More importantly however, any images or data recorded/stored from the SPY® system can't be related to features or planning marks made by surgical pens.
Without the requirement for the mark from a pen to be simultaneously visible to both a user and a fluorescence camera, the need for such a device for a surgical application may be unnecessary. Use of the SPY® Imaging System to evaluate and document the revascularization of a surgical site has created such a need.